Ebola virus in Sierra Leone is killing dozens by the week. Medical workers have responded by expanding a field hospital, taking extraordinary measures to contain infection.

ARUN RATH, HOST:

This is WEEKEND EDITION from NPR News. I'm Arun Rath. The worst Ebola outbreak ever recorded continues to spread in West Africa. And medical workers in Sierra Leone have responded by expanding an extraordinary field hospital. It opened less than a month ago, but it now has the largest Ebola isolation unit ever built, with 64 beds. NPR's Jason Beaubien visited and describes for us the infection control measures that go into treating this highly contagious disease.

JASON BEAUBIEN, BYLINE: The basic design principle of the Doctors Without Borders Ebola treatment center in Kailahun is keep the Ebola virus trapped in the middle of the compound. Patients who have ebola stay in large white tents inside that isolation zone. The medical staff go in and out to treat them.

SEBASTIAN STEIN: Going into this area involves significant risk, unless you know how to protect yourself.

BEAUBIEN: Sebastian Stein is the sanitation coordinator for the facility, which means it a large part of his job is infection control.

STEIN: Everything you want to do inside the high risk zone, where the patients are, is a tremendous undertaking.

BEAUBIEN: It's a tremendous undertaking because anyone who goes in - doctors, nurses, cleaners, construction repair men - have to wear protective suits that cover every inch of their bodies. The protective gear includes gloves, face masks and goggles.

This person, now - they're putting their goggles on right now. That was the last bit of skin we were seeing, yeah?

STEIN: That's right. And you see, now, that his colleague is now checking to see that there is absolutely no skin exposed. Everything is covered up.

BEAUBIEN: Ebola spreads by contact with bodily fluids - blood, vomit, diarrhea - but also through sweat or tears. Many of the early victims in Sierra Leone were healthcare workers who were caring for people infected with the virus. Usually Ebola kills more than half the people who get it. And so far, more than 600 people have died in this outbreak across West Africa.

STEIN: So every day, we have to send in our teams to go and wash the bodies, disinfect the bodies and then hand them over to either the families or to the officials here. And this is - it's a grim task.

BEAUBIEN: Stein says, five or six patients are dying at this facility every day.

STEIN: Ebola's a horrible disease, and, yeah, what you see is not something that is pleasant.

BEAUBIEN: All that separates the tents in the isolation zone from the rest of field hospital are two strands of orange plastic fencing with a six-foot no man's land in between. He says, this waist high orange mesh is really just to make it incredibly clear what's outside the isolation zone and what's inside.

STEIN: And then everything you bring inside - every tool, every piece of material - it stays inside. It doesn't come out.

BEAUBIEN: A doctor stands on the inside of the orange fence in his full protective suit and shouts out the clinical symptoms of each of his patients.

UNIDENTIFIED MAN 1: Nausea.

UNIDENTIFIED MAN 2: Nausea.

UNIDENTIFIED MAN 1: Vomiting and diarrhea for four days.

BEAUBIEN: A nurse on the outside transcribes the information to the patients' medical files. Stein says, staff members can only stay in the isolation zone for 30 or 40 minutes at a time.

STEIN: Working inside is hard because these suits are completely sealed, so it's like being in a sauna. And under the sun here in Sierra Leone, you really heat up, and you sweat a massive amount of water.

BEAUBIEN: But before they can exit, they have to strip off the protective gear in a way that makes sure the virus doesn't come out with them. A worker leaving the isolation zone sprayed down with a chlorine solution. He then slowly peels off the layers of gloves and masks and coveralls. Stein says, the decontamination zone is one of the most dangerous areas of the entire facility because the workers are often exhausted and prone to mistakes. Jason Beaubien, NPR News, Kailahun, Sierra Leone.

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